1. Field of the Invention
The present invention relates to an image display device, particularly to an image display device connected to an image archive device that stores multiple image data.
2. Description of the Related Art
There have heretofore been medical image display devices that display medical images. Such medical image display devices acquire an image to be displayed from a medical image archive device connected to a network. This image acquisition is generally of an on-demand type, in which a user designates a required image using web technology or the like and receives that image only.
Moreover, conventional technologies (e.g., Japanese published unexamined application No. 2005-316990) include picture archiving and communication systems (PACS). In this system, a medical imaging device such as an X-ray CT (computed tomography) device or an MRI (magnetic resonance imaging) device, an image archive device as a file server, and a work station are connected together via a LAN (local area network). Image data generated from the medical imaging device are sent to the image archive device. The work station requests the image archive device to send data, receives image data via LAN, and displays an image on a monitor.
Images sent from the image archive device to the work station via the LAN include uncompressed images in which image data are not compressed as well as reversible and irreversible images in which image data are compressed. Higher levels of compressibility of the image data result in lower data volume and reductions in the time generally required for reception.
A reversibly compressed image is a compressed image that can be compressed without losing any of the original data and can completely restore the original data. On the other hand, an irreversibly compressed image is a compressed image in which the image before compression and the image after compression and decompression are not completely matched. An irreversibly compressed image can obtain higher compressibility than a reversibly compressed image, allowing the data volume to be smaller.
As a measure for enhancing the image display speed of the work station between receiving image data from the image archive device and displaying it on the monitor, there is a method of receiving irreversibly compressed images with smaller data volumes. However, this involves the disadvantage of deteriorating the quality of the displayed images.
The image compression technology known as JPEG2000 (Joint Photographic Experts Group 2000) can perform reversible compression and irreversible compression freely, making it possible to completely restore the original image and thereby resolving the disadvantage of deteriorating the quality of the displayed images.
However, with the aforementioned conventional image display device, when image data are designated via an input from a manipulation part, those designated image data are received from the image archive device and the received image data are displayed. Thus, there has been a problem that it takes time to complete the display of the image data after designating the image data.
Moreover, if a portion of a file is acquired using JPEG 2000 image compression technology, there has been a problem that the user is required to perform special manipulations in order to scroll an irreversibly compressed image into an uncompressed image.